Option 1: The World Environment Day is celebrated on June 5th every year to raise awareness and take action on environmental issues.

Option 2: The World No-Tobacco Day is observed on May 31st to spread awareness about the health risks associated with tobacco use and encourage people to quit smoking.

Option 3: The International Day against Drug Abuse and Illicit Trafficking is observed on June 26th to raise awareness about the dangers of drug abuse and the illegal drug trade.

Option 4: The correct answer is the International Youth Day. It is celebrated on August 12th every year to recognize and promote the role of young people in society, and to address the challenges they face. This day focuses on issues such as education, employment, poverty, and mental health affecting the youth. It also provides a platform to amplify youth voices and advocate for their rights and well-being.

In conclusion, while options 1, 2, and 3 correspond to different significant days, the correct answer for August 12th is option 4, the International Youth Day.